Internal-combustion engine



a J. DAVIDSON INTERNAL comsuswxon ENGINE Filed Sept. 10. 1925 2 Sheets-Sheet 1 Fig.2.

May 12, ,1925.

J. DAVIDSON INTERNAL COMBUSTION ENGINE Filed Sept. 10, 1925 2 Sheets-Sheet 2 //WEI\{TOR v a/m ,Faaulaon Patented May 12, 1925.

UNITED STATES I 1,537,805 PATENT OFFICE.

JOHN DAVIDSON, OF TUTBD'BY, BURTON, ENGLAND, ASSIGNOR TO THE RECORD CRUDE OIL ENGINE COMPANY, LIMITED, OF LONDON, ENGLAND.

INTERNAL-COMBUSTION ENGINE.

Application filed September 10, 1923.

To all whom it may concern:

Be it known that I, JOHN DAVIDSON, a British subject, residing at The Elms, Tutbury, Burton, England, have invented cer- 6 tain new and useful Improvements in Internal-Combustion Engines, of which the following is a specification.

Internal combustion engines have already been constructed in which two or more working pistons are connected with a charging piston, all three pistons reciprocating simultaneously in the same direction. I have found, however, that a design of engine of this type which is capable of per object to provide improvements whereby the forming satisfactory service when driven by an explosive mixture at low horsepower is subject to serious detect when more heavily built or adapted for use on the Diesel or. semi-Diesel principle. On the one hand, the extreme accuracy of workmanship necessary to prevent binding of one or other of the pistons renders it very diflicult to .trial sca e, and on the other hand even when the necessary accuracy has been obtained, the extent of distortion arising from unequal expansion between the hotworking pistons and cylinders and the comparatively cool charging ist'ons and cylinders is such in the case 0 large en ines as to render smooth and economical woidking very problematical. The present invention has for its primary above objections may be avoided in rge engines and engines of the Diesel and semi- Diesel type constructed as above described.

The invention accordingly consists pri marily' in the arrangement wherein the working pistons are laterally movable rela tively to the charging pistons. I find that this improvement is practically essential with all engines of the said type working on the Diesel or semi-Diesel rinciple' and is of considerable value with iarger engines of the ordinary ex losive mixture type.

A. further ob ect of the resent invention is to avoida further difiicu lty met chiefly in engines of the Diesel or semi-Diesel type wherein the ex losion chamber is required to be consider-a 1y less than in the case of explosive mixture engines. In engines of the type set forth, the ex losive mixture has been led through ports in the wall of one workin c linder and out through ports in the wal 0 another working cylinder, so that roduce such engines on an indus-' Serial No. 661,919.

partition between the two cylinders. For i the purpose of reducing the size of this space it is impracticable to raise the partition and pistonrstroke beyond certain lim' its, as otherwise the flow of gas on inlet and exhaust is thereby seriously impeded, and the present invention accordingly consists in the construction whereby the top of each piston extends beyond the working face and thus beyond the partition between the two cylinders when at the to of its stroke. Preferably this is accomplished by provid ing a mutilated dome-shaped top, the dome corresponding in shape to the corresponding element of a curved surface constituting the roof of the explosion chamber but having a cut-away face at the side adjoin ing the aforesaid partition.

The invention is illustrated in the accom-'- panying drawings in which Figs. 1 and 2 represent sectional views in plan and elevation and Fig. 3 a side view of anengine of the semi-Diesel type, Fig. 4.- being a view of a detail. Fig. 5 is a sectional detail showing the' manner of connecting the pietons to .permit a relative tilting movement thereof.

The engine here illustrated comprises two units 1, 2 which each comprise a pump cylinder 3 and two chargin cylinders 4, 5 rlgid therewith arran ed si e by side above the pump cylinder. n each unit reciprocates a pump or charging piston 6 and two working pistons 7, 8 which are fixed to and is sucked in through inlet 9 by the pump .pis'ton throu h the port 10 which'has just been opened y the slide valve 11. As the pump descends the slide valve also descends fora time but afterwards rises again and.

closes the port 10 and, in its further movement, when the piston commences its return stroke, puts the port 10 into communication with the port 12 by means of the annular channel 135. Thus the charge of air which has been sucked into the left-hand pum chamber 3 is compressed and discharge into the chamber M,Figs. 2 and 3, whence it is delivered, as the piston 7 descends, into the depression of the valve. Fuel is injected through the passage 17 and fired by the hot bulb 18, Fig. 3 all inknown manner Now according to the present invention the working pistons '7, 8 are mounted on the pump pistons 6 by means permitting relative movement thereof so that the said moving parts in heavy engines are capable of a certain amount of flexible adjustment to irregularities in the construction of the cyl-, inders an'd/or distortion of the cylinders and pistons due to unequal expansion during working. In the form shown this .is accomplished by providing the pistons 7, 8

with an inwardly-extending annular flange 19 adapted to be engaged by a flanged cap 20, Fi 4, held down by a bolt 21 passing throng the working face of the pump piston 6.. Inthe form shown, the engaglng surfaces of the pump piston 6 and the lower faces of the working pistons and caps are plane and transverse to the axis of the pistons so that relative movement is confined to a horizontal plane at right angles to the axis of the pistons.

It is to be understood, however, that I do not wish to be limited 'to movement in a horizontal -plane as I may provide a slight- 1y spherical or cylindrical surface of cleavage between the elements intended to be capable of relative movement so that a certain amount of tilting will be made possi ble for the pistons 7, 8, as shown in Fig. 5. Alternatively, the working pistons may be hingedly mounted on short connecting rods ,cOnstr-nction the air entering the cylinder 1 andf exhausted through the cyli'nder 5 is required to pass through the space between the topof thepartition 22 formed by. the

cylinder walls, 4, 5 and the roof 23 0f the common explosion chamber. On the one hand, for free movement of the air it is desirable that the distance between the partition 22 and roof 23 be considerable, but with Diesel and semi-Diesel engines it-is desirable that the effective size of the explosion chamber be reduced to an extent conflicting with the aforesaid requirement, and the present invention further consists in the constructionin engines of the above j type haying a plurality of working pistons,.

whereby'the tops of said pistons are extended above the working faces and therefore above the top of the partition 22 so as to-restrict the effective size of the explosion assage of chamber without restricting the the air when the pistons are wit drawn.

In the form shown, the roof 23 of the explosion chamber is formed to a concave surface with which the dome-shaped tops 24. of the pistons, 7, 8 are sha ed to correspond. The said tops rise in heig 1; from the outer to the inner edges as viewed in Fig. 1 and there terminate in cut-away faces which face each other across the partition 22. The cut-away faces may be generally plane or cylindrical or I may if desired form concave spherical or like mutilations designed so as to give the desired restriction of the size of the explosion chamber.

Although the invention has been described with regard to an engine com rising two units, it is obviously applicab e to an engine comprising one unit (in which case the underside of the pump piston would effect the scavenging) and to engines comprising multiple unlts. Where more than two working pistons are mounted on one pum piston, I prefer to employ an even num er scavenged in pairs as above described so that the arrangement of the dome-shaped pistons would be applicable thereto without alteration. The movable mounting of the working piston is also applicable to engines having only one working piston mounted on an annular charging piston in each unit.

I claim 1. In an internal combustion engine, a

working piston, a charging piston connected therewith, a working cyllnder, a charging cylinder rigid therewith, the working piston being mounted on the charging piston.by

means permitting of a bodily movement of the charging piston over the face of the working piston in such a manner that the aIIKlS' (()1f the charging pistonis laterally disace p 2. In an internal combustion engine, a charging piston a charging cylinder, a plurality of working pistons connected to the charging piston, a lurality of working cylinders rigid with t e charging cylinder and having a common explosion chamber, means whereby the working pistons are ca able of lateral movement relatively to said 0 arging piston in a plane transverse to the axes of said piston.

3. In an'internal combustion engine, a charging piston a charging cylinder, a plurality of'working pistons connected to the charging piston, a plurality of working cylinders rigid with the charging cylinder and having a common explosion chamber, means whereby the Working pistons'are capable of tilting movement relatively to said charging pisto r 4. In an internal combustion engine, a charging piston, a charging cylinder, a pair of working pistons secured to said charging piston a pair of workin cylinders rigid with said charging cylinder and having a common explosion chamber, means for the ingress of fluid into one of said working cylinder and means for the exhaust of fluid from the other of said working cylinders,

said working pistons having tops extending upwardly beyond their working faces and above the partition formed by the adjacent walls of said Working cylinders, when the pistons are in firing positions.

charging piston, a charging cylinder, a pair' of working pistons-secured to said charging piston a pair of working cylinders rigid with said charging cylinder and having a common explosion chamber, means for themgress of fluid into one of said working cylinders and means for the exhaust of fluid from the other of said working 1: linders said working pistons having exten ed to s shaped to correspond with the shape of t e roof of the explosion chamber, said tops having cut-away faces facing each other.

6. In an internal combustion engine, a

charging cylinder, a plurality of working cylinders rigid therewith, a charging piston in the charging cylinder, a plurality of working pistons mounted on said charging piston and operating in the working cylinders, and means connecting the working pistons and charging piston to bodily movement of the worklng pistons over the face of the charging piston in a 'mannerrto permit lateral displacement of the axes of the workin pistons.

Intestimony whereo I aflix my sgnat'ure.

" JOHN DAVIDSON.

permit of a 

